Commentary for Numbers 16:4

ויפל על פניו [AND WHEN MOSES HEARD IT,] HE FELL UPON HIS FACE because of the rebellion, for this was already the fourth offence on their part: when they sinned by worshipping the Golden Calf, it states, (Exodus 32:11) "And Moses besought [the Lord]”; in the case of the “people who complained”, (Numbers 11:1) it states: “and Moses prayed”; at the incident of the “spies”, (Numbers 14:13) “And Moses said unto the Lord, ‘When the Egyptians shall hear it ... [and now I beseech Thee etc.]”; but now at the rebellion of Korah, his hands sank down (he felt himself powerless) A parable! This may be compared to the case of a prince who sinned against his father and for whom his (the father’s) friend gained forgiveness once, twice, three times. When he offended for the fourth time the friend felt himself powerless, for he said, “ How long can I trouble the king? Perhaps he will not again accept advocacy from me!” (Midrash Tanchuma, Korach 4).

AND WHEN MOSES HEARD IT, HE FELL UPON HIS FACE. It does not say “and they fell [upon their faces],” for Aaron in his modesty and holiness did not utter a word throughout this whole controversy, but he was as one that held his peace,⁴¹I Samuel 10:27. and who admits that Korach’s status was greater than his own, and he only acted according to Moses’ behest, fulfilling the king’s decree.

וישמע משה ויפל על פניו. When Moses heard this he fell upon his face. Why did the Torah have to tell us that Moses heard what Korach said? Korach and company had been described as addressing Moses; it is obvious that he heard what they said. Furthermore, what precisely is the meaning of Moses "falling?" It appears that inasmuch as the scoffers had not yet completed what they came to say the Torah wanted to inform us that Moses already understood their meaning even though they had not spelled it out as yet. Accordingly, we may assume that Moses "fell" already as soon as Korach accused him of having raised himself above the people. He wanted to demonstrate that far from raising himself above the people he humbled himself and made himself equal to the dust of the earth like a slave prostrating himself before a master. As far as the second accusation was concerned, i.e. the fact that Aaron was the High Priest, he told the rebels that already on the morrow G'd Himself would demonstrate whether Aaron's appointment was an act of nepotism or any other form of autocratic behaviour, or if he had been appointed at the command of G'd Himself.